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Kenneth Duy Tran, Ray Lum, Megan Bauer, Christine W Sindt, Kuangmon Ashley Tuan; Characterization of impression-based scleral lens movement during wear. Invest. Ophthalmol. Vis. Sci. 2020;61(7):1478.
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© ARVO (1962-2015); The Authors (2016-present)
Scleral lenses have been used to compensate higher order aberrations but depend on stability and positional predictability on eye. There are limited methods to stabilize the movement of scleral lenses, especially with asymmetric scleral profiles. Here we characterize the positioning of impression-based scleral lenses as one platform that may minimize movement during wear.
Seven healthy adults with no history of ocular pathology were fit with impression-based scleral lenses using EyePrint Designer software. Lenses were 17mm in diameter with anterior surface modifications to track position (stability marks). High-resolution videos in primary gaze (12 seconds, 100 frames/sec) were acquired following adequate settling (>30 minutes of wear). Dynamic position analysis using custom software compared user-defined iris references to stability marks to quantify decentration (microns) and rotation (degrees). Static position analysis compared the geometric center of the lens to the pupil center using EyePrint Designer software. Measurements were repeated over several sessions (2-6).
The lenses (n=12) returned to settled positions following blink within an average 0.12 seconds (sd= 0.04 seconds). Translation from the settled position between blinks averaged 5.40 microns (sd=2.16 microns) and was unspecific in direction. Average magnitude of rotation during wear was 0.03 degrees (sd=0.11 degrees). Static positional variability between sessions (n=22) averaged 150.37 microns (sd=79.45 microns) and was unspecific in direction. No adverse ocular effects were observed upon slit lamp evaluation of all participants.
By quantifying the dynamic positioning of impression-based scleral lenses, we observed minimal translation or rotation of this design during wear. In addition, the repeatability of the overall lens positioning between sessions was high. Notably, these findings demonstrate the potential for advanced optical design on this platform because of the relative stability and positional predictability during wear.
This is a 2020 ARVO Annual Meeting abstract.
Left: Dynamic position analysis software with lens reference points (red) and iris reference points (blue). Right: Static position analysis, comparing lens geometric center to pupil center.
Dynamic position output visually demonstrating positional and rotational change during wear.
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